Marine porifera have continued to be an increasingly important source of new nitrogen heterocyclic compounds with significant biological activities. Recent examples include the cytotoxic constituents pateomine (Mycale sp.), a pyridine betaine (Microcosmus vulgaris), topsentin B2 (Rhaphisia lacazei), asmarine A (Raspailia sp.), cyclic guanidines (Monanchora sp.), the antiviral dragmacidin F (Halicortex sp.) and the isolation and structure determination of cribrostatins 4 (1) and 5 (2) from the Republic of Maldives blue-colored sponge Cribrochalina sp. (West, L.; et al., J. Org. Chem. 2000, 65, 445-449; Aiello, A., et al., J. Nat. Prod. 2000, 63, 517-519; Casapullo, A., et al., J. Nat. Prod. 2000, 63, 447-451; Yosief, T., et al., J. Nat. Prod. 2000, 63, 299-304; Braekman, J., et al., J. Nat. Prod. 2000, 63, 193-196; Cutignano, A., et al., Tetrahedron 2000, 56, 3743-3748, Pettit, G., et al., J. Nat. Prod. 2000, 6, 793-798.)